IWF Considerations

When the system performs a local policy lookup for an incoming SIP or H.323 call and determines an ENUM/LRT server is the next hop, it queries that ENUM/LRT server. The response will include the URI scheme, indicating the next hop protocol and the hostname/IP address representing the next hop. For cases where the incoming call signaling protocol and the URI scheme of the ENUM/LRT response are the same, the call requires no interworking. The Oracle® Enterprise Session Border Controller can simply route the egress call leg to the specified next hop.

Interworking is required when the incoming signaling protocol and the URI scheme of the ENUM/LRT response do not match. When the responses do not match, the Oracle® Enterprise Session Border Controller interworks between SIP and H.323 to route the call to the appropriate next hop.

The Oracle® Enterprise Session Border Controller also compares the URI scheme returned in the ENUM/LRT response to the application protocol specified in the policy attributes. If the URI scheme is SIP, but the policy attributes indicate H.323, the route is deemed invalid. The same is true for an H.323 URI scheme and SIP route.